From patchwork Fri Jun 26 19:32:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Walker X-Patchwork-Id: 39806 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 74DD6388C017; Fri, 26 Jun 2020 19:32:39 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 74DD6388C017 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1593199959; bh=efBXlb0wW094ARnZ8opWq+dXytJnFABb43DVraNGef4=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=YS4+sPGvy1iMdgaYbHs4/hTrfcnh7o9T61TfDUTzSd/EWsPuykQTjNm533aFKYZHD 8Mj1VMenYV4RO1RZxHwsvcGjLsuUSbDV5aOGf3kgKKCjKyPG7bTdyPl84QKqPmXftS h5XCR44ev8NFGBHh5lZ0D0LrcsQJyUWQK9wXzqEk= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from rcdn-iport-7.cisco.com (rcdn-iport-7.cisco.com [173.37.86.78]) by sourceware.org (Postfix) with ESMTPS id C4B7F386F83E for ; Fri, 26 Jun 2020 19:32:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org C4B7F386F83E X-IronPort-AV: E=Sophos;i="5.75,282,1589241600"; d="scan'208";a="780331164" Received: from alln-core-8.cisco.com ([173.36.13.141]) by rcdn-iport-7.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 26 Jun 2020 19:32:34 +0000 Received: from zorba.cisco.com ([10.24.15.228]) by alln-core-8.cisco.com (8.15.2/8.15.2) with ESMTP id 05QJWSW4030756; Fri, 26 Jun 2020 19:32:29 GMT To: libc-alpha@sourceware.org Subject: [RFC PATCH 1/3] Segfault when dlopen with RTLD_GLOBAL in dlmopened library Date: Fri, 26 Jun 2020 12:32:26 -0700 Message-Id: <20200626193228.1953-2-danielwa@cisco.com> X-Mailer: git-send-email 2.17.1 X-Auto-Response-Suppress: DR, OOF, AutoReply X-Outbound-SMTP-Client: 10.24.15.228, [10.24.15.228] X-Outbound-Node: alln-core-8.cisco.com X-Spam-Status: No, score=-18.9 required=5.0 tests=BAYES_00, DKIMWL_WL_MED, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_PASS, TXREP, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Daniel Walker via Libc-alpha From: Daniel Walker Reply-To: Daniel Walker Cc: Conan C Huang , Jeremy Stenglein , xe-linux-external@cisco.com Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" From: Conan C Huang GLIBC Bugzilla: 18684 When a dlmopenend library calls dlopen with RTLD_GLOBAL flag, dynamic loader segfaults. Loader is trying to add new linkmap into new namespaces _ns_main_searchlist. But this _ns_main_searchlist is not initialized during dmopen call (when namespace was created). Loader needs to initialize _ns_main_searchlist during dlmopen when a new namespace is created. As well as clean up when that namespace is deleted. --- elf/dl-close.c | 7 ++++++- elf/dl-open.c | 4 ++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/elf/dl-close.c b/elf/dl-close.c index 73b2817bbf..675f2fbac8 100644 --- a/elf/dl-close.c +++ b/elf/dl-close.c @@ -802,7 +802,12 @@ _dl_close_worker (struct link_map *map, bool force) if (__builtin_expect (ns->_ns_loaded == NULL, 0) && nsid == GL(dl_nns) - 1) do - --GL(dl_nns); + { + --GL(dl_nns); + + /* Clear main search list */ + GL(dl_ns)[GL(dl_nns)]._ns_main_searchlist = NULL; + } while (GL(dl_ns)[GL(dl_nns) - 1]._ns_loaded == NULL); /* Notify the debugger those objects are finalized and gone. */ diff --git a/elf/dl-open.c b/elf/dl-open.c index 8769e47051..9b3606c491 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -921,6 +921,10 @@ no more namespaces available for dlmopen()")); assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT); + /* Initialize main search list in new namespace */ + if (__glibc_unlikely (GL(dl_ns)[nsid]._ns_main_searchlist == NULL)) + GL(dl_ns)[nsid]._ns_main_searchlist = &(args.map->l_searchlist); + /* Release the lock. */ __rtld_lock_unlock_recursive (GL(dl_load_lock));